The present invention relates to a method of forming novel Si--O containing coatings. The method comprises converting hydrogen silsesquioxane resin into Si--O containing ceramic coatings in the presence of hydrogen gas. The resultant coatings have desirable properties.
The use of silica-containing ceramic coatings derived from hydrogen silsesquioxane resin on electronic devices is known in the art. For instance, Haluska et al. in U.S. Pat. No. 4,756,977 describe processes for forming coatings on electronic devices which comprise diluting hydrogen silsesquioxane in solvents, applying the solutions to substrates, evaporating the solvents and heating the coated substrates to a temperature of about 150.degree. to about 1000.degree. C. in air. This patent, however, does not describe the use of hydrogen gas in the conversion of hydrogen silsesquioxane resin into the silica containing ceramic.
The conversion of hydrogen silsesquioxane resin to a Si--O containing ceramic in other environments is also known in the art. For instance, European Patent Application No. 90311008.8 teaches the conversion of hydrogen silsesquioxane resin to a Si--O containing ceramic by heating a substrate coated with the resin in an inert gas atmosphere. This patent too, however, does not describe the use of hydrogen gas in the pyrolysis atmosphere curing conversion of hydrogen silsesquioxane resin into the silica containing ceramic.
The present inventors have now discovered that hydrogen silsesquioxane resin can be converted into Si--O containing ceramic coatings with improved properties by heating in an environment containing hydrogen gas.